Vic, Thanks for the comments. Last one first, the signal is clean, pick up in a spectrum analyzer shows the spurs are well below 40 db down. Is there an rf conducting grease that should be used on th
All, I am trying to tune bandpass filters. I have a network analyzer and can see both reflected and transmitted signal. My questions are: If the filter were tuned and terminate properly in the bandpa
All, I would like to wind a broad band HF, 160 to 10, transformer. What core material is best for this range? Is the way to wind this a trifler winding (9:1) in an autotransformer configuration? Than
Thanks for the reply, I am experimenting reworking a Heathkit 104 (not A) front end. That front end had a reputation for being deaf. I believe it was due in large part to a gross impedance mismatch b
All, A follow up, I wound a quintfiler toroid in an auto transformer configuration. Does that configuration have a 125:1 ratio? Dan _______________________________________________ Amps mailing list A
Manfred, How many turns were on the 50 ohm winding? Thanks, Dan _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
Peter, Are you saying number 2, red, and number 6, yellow, material cores are not suitable for low power broadband transformers? Or is this a power and heating issue that is not relevant at low power
All, I am trying to figure where in a 10 meter power amp with MRF454s the low band frequency limit is? This is a relatively simple amp. The circuit looks identical to the classic Motorola Granberg EB
Does anyone know what an ST 681033A is a match for? I suspect is is a match for an MRF150. Thanks, Dan _______________________________________________ Amps mailing list Amps@contesting.com http://lis
Does anyone know the common part number for an ST 681033A. If not what part is it closest to? Thanks, Dan _______________________________________________ Amps mailing list Amps@contesting.com http://
This is a general question regarding 'testing' RF power MOSFETs 1. There appears to be a difference between the MRF150 and the ST equivalent based on the 'simple' test of placing the negative lead of
I have a couple solid state RF power amps to test. One question is: What is their bandpass? I connected a network analyser drive to the output and then took the NA input of the collectors. Accounting
Is there a straightforward practical or operational description of the difference between 'red' cores and 43 material. The magnetic differences are large. However, the 'red' cores are used in low pow
Thanks to all of you for the replies. The first interest is to build and test a 300 watt input and output transformer pair. The reason I chose #43 to discuss was it was mentioned in at least one of t
Hello, this is a question relating to a bifilar winding around various torroid cores. The winding was made from two pieces of #26 enamel wire about 6 inches long and wound at 3 to 4 turns per inch. T
I have an older solid state amp based on a pair of MRF 454s. The amp is missing three common design features found in most similar HF power amps, a bias circuit for the base, negative feedback, and a
All, I have an ENI power amp with what look like SD 1726 transistors in a class C configuration. The circuit is pretty standard, however there are 3 ohm resistors between the base and the emitters. C
All, I am converting a TH430 based Class C amplifier to Class AB. The basic circuit is a traditional single stage layout with input and output binocular transformers. Things are proceeding, however t
Manfred, Thank you again for your input. The insight into the bias circuit was very helpful. I replaced the curve tracer with a variable power supply; that improved the response considerably. The pla
I am trying to convert an ENI TH430 based RF power amp to 'mimic' the EB 63 circuit. Can someone provide a starting point for the purpose and selection of C8 and C9 between collector and emitter? Wha